The present application is related to four co-pending and commonly-owned applications filed on even date herewith, the disclosure of each is hereby incorporated by reference in their entirety, these four applications being respectively entitled:
(1) xe2x80x9cSURGICAL STAPLING INSTRUMENT INCORPORATING A TAPERED FIRING BAR FOR INCREASED FLEXIBILITY AROUND THE ARTICULATION JOINTxe2x80x9d to Frederick E. Shelton IV, Mike Setser, and Bruce Weisenburgh;
(2) xe2x80x9cSURGICAL STAPLING INSTRUMENT HAVING ARTICULATION JOINT SUPPORT PLATES FOR SUPPORTING A FIRING BARxe2x80x9d to Kenneth S. Wales and Joseph Charles Heuil;
(3) xe2x80x9cSURGICAL INSTRUMENT INCORPORATING AN ARTICULATION MECHANISM HAVING ROTATION ABOUT THE LONGITUDINAL AXISxe2x80x9d to Kenneth S. Wales, Douglas B. Hoffman, Frederick E. Shelton IV, and Jeff Swayze; and
(4) xe2x80x9cA SURGICAL INSTRUMENT WITH A LATERAL-MOVING ARTICULATION CONTROLxe2x80x9d to Kenneth S. Wales.
The present invention relates in general to surgical stapler instruments that are capable of applying lines of staples to tissue while cutting the tissue between those staple lines and, more particularly, to improvements relating to stapler instruments and improvements in processes for forming various components of such stapler instruments that include an articulating shaft.
Endoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).
Positioning the end effector is constrained by the trocar. Generally these endoscopic surgical instruments include a long shaft between the end effector and a handle portion manipulated by the clinician, this long shaft enables insertion to a desired depth and rotation about the longitudinal axis of the shaft, thereby positioning the end effector to a degree. With judicious placement of the trocar and use of graspers, for instance, through another trocar, often this amount of positioning is sufficient. Surgical stapling and severing instruments, such as described in U.S. Pat. No. 5,465,895, are an example of an endoscopic surgical instrument that successfully positions an end effector by insertion and rotation.
Depending upon the nature of the operation, it may be desirable to further adjust the positioning of the end effector of an endoscopic surgical instrument rather than being limited to insertion and rotation. In particular, it is often desirable to orient the end effector at an axis transverse to the longitudinal axis of the shaft of the instrument. The transverse movement of the end effector relative to the instrument shaft is conventionally referred to as xe2x80x9carticulationxe2x80x9d. This articulated positioning permits the clinician to more easily engage tissue in some instances. In addition, articulated positioning advantageously allows an endoscope to be positioned behind the end effector without being blocked by the instrument shaft.
While the aforementioned non-articulating stapling and severing instruments have great utility and may be successfully employed in many surgical procedures, it is desirable to enhance their operation with the ability to articulate the end effector, thereby giving greater clinical flexibility in their use. Articulating surgical instruments generally use one or more firing bars that move longitudinally within the instrument shaft and through the articulation joint to fire the staples from the cartridge and to cut the tissue between the innermost staple lines. One common problem with these surgical instruments is control of the firing bar through the articulation joint. At the articulation joint, the end effector is longitudinally spaced away from the shaft so that the edges of the shaft and end effector don""t collide during articulation. This gap must be filled with support material or structure to prevent the firing bar from buckling out of the joint when the single or multiple firing bars is subjected to longitudinal firing loads. What is needed is a support structure that guides and supports the single or multiple firing bars through the articulation joint and bends or curves as the end effector is articulated.
U.S. Pat. No. 5,673,840 describes a flexible articulation joint that is formed from an elastomeric or plastic material that bends at the flexible joint or xe2x80x9cflex neckxe2x80x9d. The firing bars are supported and guided through a hollow tube within the flex neck. The flex neck is a portion of the jaw closure mechanism and moves longitudinally relative to the end effector, shaft, and firing bars when the jaws are closed on tissue. The firing bars then move longitudinally within the flex neck as the staples are fired and tissue is cut.
U.S. Pat. No. 5,797,537 to Allen describes an articulation joint that pivots around a pin, rather than bends around a flex joint. In this instrument, firing bars are supported between a pair of spaced support plates connected at one end to the shaft and at another end to the end effector. At least one of those connections is a slidable connection. The support plates extend through the articulation joint adjacent to the flexible drive member in the plane of articulation such that the support plates bend through the gap in the plane of articulation and the flexible firing bar bends against the support when the tip is articulated in one direction from its aligned position. U.S. Pat. No. 6,330,965 from U.S. Surgical teaches the use of support plates that are fixedly attached to the shaft and slidably attached to the end effector.
Although these known support plates guide a firing bar through an articulation joint, it is believed that performance may be enhanced. In particular, generally support plates and firing bar are sufficiently flexible in order to allow articulation without an undue amount of force. In addition, these components are sized and spaced for endoscopic use through a cannula passageway. Consequently, the plates and firing bar tend to come into contact with one another when articulated, creating binding and friction.
Consequently, a significant need exists for an improved articulation mechanism for a surgical instrument mechanisms that provides enhanced support to a firing bar through the articulation joint with reduced friction.
The invention overcomes the above-noted and other deficiencies of the prior art by providing an articulating surgical instrument that actuates an end effector with a longitudinally translating firing mechanism advantageously supported through an articulation mechanism by flanking support plates. In order to avoid pinching the firing mechanism as it longitudinally translates between articulated support plates, a retaining member is inserted between the support plates. The retaining member assists in providing structural support across the articulation member as well as spacing the support plates so that friction on the firing mechanism is reduced.
In one aspect of the invention, a surgical instrument has a handle portion that produces an articulation motion and a firing motion, both of which are transferred through a shaft to an articulation mechanism. The articulation mechanism responds to the articulation motion to rotate an end effector from the longitudinal axis of the shaft. A firing mechanism responds to the firing motion and is coupled for movement through the articulation mechanism and the end effector. A pair of support plates flank the firing mechanism across the articulation mechanism, spaced by a retaining member proximate to the firing mechanism. Thus various types of actuated diagnostic or therapeutic end effectors may be incorporated into an articulating surgical instrument without buckling at the articulation mechanism, even with high firing forces and reduces component dimensions for endoscopic use.
In another aspect of the invention, a surgical instrument has a handle portion that produces a firing motion, a closing motion, and an articulation motion, each transferred through a shaft. An articulation mechanism distally coupled to the shaft pivots an end effector in response to the articulation motion. The end effector includes an elongate channel coupled to the shaft, an anvil that is pivotally coupled to the elongate channel and that is responsive to the closing motion from the shaft. A firing device has a distally presented cutting edge longitudinally received between the elongate channel and the anvil. An articulation mechanism pivots the elongate channel from the shaft in response to the articulation motion. A pair of support plates flank the firing mechanism across the articulation mechanism, spaced apart by a retaining member. Thereby, an improved stapling and severing instrument may incorporate a firing device that withstands high firing loads yet does not introduce significantly increased firing forces when articulated.
These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.